Patent GB-230128-A (GB)
Title: Improvements in dyeing processes
IPC: C09B51/00
Filed: 1923-10-22
Abstract: Gelatine is dyed by means of phenols of the benzene series treated either on the fibre or in the bath in the cold or with application of heat with nitrites or nitrous acid in presence of metallic salts or oxides.  Amines may be employed instead of phenols but at a raised temperature so as to form the corresponding phenol.  Gaseous nitrous acid may be employed carried by a stream of air, steam, or other gas. In general the bath is composed of a phenol or amine, metal salt, nitrite, and an acid or acid salt such as bitartrate, but if a phenol-acid be employed the acid may be omitted.  Reference has been directed by the Comptroller to Specification 4534/98, [Class 15, Bleaching &c.].ALSO:Animal and vegetable fibres, feathers, furs, hairs, leathers, artificial silks, wood, gelatines, &c. are dyed or printed by means of phenols of the benzene series treated either on the fibre or in the bath, in the cold or with application of heat with nitrites or nitrous acid in presence of metallic salts or oxides. Amines may be employed instead of phenols but at a raised temperature so as to form the corresponding phenol.  Gaseous nitrous acid may be employed carried by a stream of air, steam or other gas. Examples show the use of the following phenols: phenol, salicylic acid, salicylaldehyde, sulphosalicylic acid, acetylsalicylic acid, antipyrine salicylate, resorcin, dinitroresorcin, diamidoresorcin and their salts and the use of amines is exemplified by aniline.  The following metals may be employed:-copper, silver, gold, zinc, barium, mercury, aluminium, tin, lead, arsenic, antimony, chromium, molybdenum, tungsten, uranium, manganese, iron in the ferrous or ferric state, nickel, cobalt and platinum in combination with any acid radicle such as chloride, sulphate, sulphide or acetate or as arsenites, arsenates, alums, chromates, bichromates, molybdates, phosphomolybdates, tungstates, uranates, permanganates, ferricyanides, or as oxides or peroxides.  When insoluble the metal compound may be enclosed in a bag in the bath.  Two or more salts or double salts may be employed.  Examples show the use of the above mentioned metal compounds and combinations to obtain a variety of yellow, brown, red, green and black tints.  In general the bath is composed of a phenol or amine, metal salt, nitrite and an acid or acid salt such as bitartrate, but if a phenol-acid be employed the acid may be omitted.  In a number of examples Rochelle salt, ammonia, and pyridine are also added to the baths. Printing may be carried out by applying a ground colour as above described and then applying a metal plate or a metal powder either with a thickening agent or fixed to a cloth or paper backing to parts to vary the colour, or the fabric may be printed in different parts with a mixture of a phenol and different metal compounds and the whole exposed to nitrous vapours, or the complete mixture as described above may be mixed with a thickening agent and printed as usual.  The printed colours may be outlined with blacks.  A further method of producing polychromatic effects consists in employing a metal exhibiting more than one valency such as iron and exposing parts of the fabric impregnated therewith to the reducing action of light.  Reference has been directed by the Comptroller to Specification 4534/98.